Carburetor



E. A. KEHOE May 29, 1956 CARBURETOR 2 Sh'ae'cs-Sheet l Filed June 26,1952 E WW mK mA. M Www JJ W May 29, 1956 z. A. KEHOE 2,747,848

` cARBuREToR Filed June 26, 1952 2 Sheets-Sheet 2 ELLswoeTH A. KEHoEUnited States Patent O CARBURETOR Ellsworth A. Kehoe, Rochester, N. Y.,assignor to General Motors Corporation, Detroit, Mich., a Corporation ofDelaware Application June 26, 1952, Serial No. 295,731 16 Claims. (Cl.261-52) This invention relates to 'carbure-tors for 'internal combustionengnes and prim-arily to such carburetors as are equipped with automaticchoice devices, through .the me- 'dium of which the mixture proportionsare varied by mechanism Operating in lresponse to variations intemperature and engine suction, in order to provide automatically amixture of proper propo'rtions for starting and operation of the engineduring the so-called Warm-up period, before the engine 'reaches normaloperating 'temperatures.

'In carburetors 'of this type this automatic regulation of mix-tureproportions is generally acco'rnplished by .the provision of anunbalanced air inlet or choke valve posi- 'tioned in the air intake of'the carburetor which is held in closed position at temperatures lower.than normal room temperature 'by a thermostat, the `closing force of'which increases as `the temperature decreases. When Ithe engine startsto operate under its own power, the force of -suction ac'ting 'directlyon .the unbalanced valve tends to open such valve and also the force ofsuction main-tained posterior to 'the throttle is effective on a pistonconnected to the 'choke valve .to exert :a force tending to open 'thevalve, which is controlled .by throttle position and engine speed.

Generally in association with most known automatic choice devices, thereis provided wh'at is termed a `fast idle mechanism. This mechanism iseffective .to bring about operation of the engine at faster than normal-idle 'speed when the engine is idling land the temperature is low, such`operation being necessary ;to prevent stalling f under 'thoseconditions. This mechanism u-sually `consists of a stepped cam which ismoved by the choice, `when .the latter is moved to closed position, tosuch a position -th'at the high point .of .the cam is opposite 'a fastidle `stop screw carried by an a-rm movable with the throttle valve.'Engagement 'of the stop screw with `this fast idle cam prevents'closing movement of .the 'throttle .to its normal ho't idle position,thus holding 'the throttle la little more open for .idling when 'coldthan when idling a't normal temperatrure.

When normal engine 'temperature is vreached and 'the `choke valve ismoved `to open position, the fast idle cam 'is moved to a position wherethe low point of 'the cam is -opposite the fast idle stop sc'rew 'sothat if 'the accelena- .tor pedal is released by .the operator, the'throttle .can move to `its normal hot idle or closed position wherel ahot idle stop serew engages -a fixed stop.

I-f :the engine is 'stopped after running at normal 'temperature thethrottle moves to its closed or hot idle position and the fast idle camis held against any movement 'toward cold idle position by engagement ofits `stepped surface with the fast idle stop screw which is movable withthe throttle. Because of `this engagement, unless the 'throttle isopened to some ex'tent before starting, the `choke Would be hel'd openvand it would be substantially impossible 'to start the engine at lowtemperatures. Accord'- ingly, it is more or less general practice for'the operator of an automotive vehicle to open .the throttle wheneverICC the engine 'is to be started, suificiently .to release the fastlidle cam from .the stop .screw, so that the choke can bel Accordingly,it is the principal object of the present invention to provide meanswhich becomes operative whenever the engine stops and before it can berestartedV 'to position 'the throttle in a sufiiciently open position-to permit the choke v'alve to move to its closed position and 'topermit the proper quantity of combustible mixture to be supplied 'tobring 'about :the easiest possible starting 'of :the engine.

It is also an object of the 'invention to provide means to prevent themovernent of the throttle to normal closed or idle position if 'there isa failure of engine suction upon release 'of the `accele'rator pedal, toprevent accidental stalling of the engine under such conditions.

In one form of the invention, a solenoid 'is 'connected vwith 'thestarter control circuit in `such .a way that it is energized whenever'said control circuit is closed to cause operation of the starting motorand actuation of such sole- 'noid moves the throttle towa-rd openposition until it occupies the best position for starting and releasesthe fast idle cam to permit movement of `the choke valve 'to its closedposition.

'In another form of the invention, 'a spring operated rod is 'n'ormallymoved by engine su'ction to 'a position where it is wholly inoperative,but whenever the engine stops 'or slows down 'to a very low speed, ismoved by 'the 'spring 'to a position to hold :the throttle 'open to thedesired extent. If upon release of 'the vaccelerator pedal to permit'closing of the throttle, the engine tends to stali, :the 'springoperated member will engage the throttle, preventing Ifull closurethereof and will prevent stalling of 'the engine. In 'the solenoidoperated device, this result is not obtained.

Other objects and advantages of 'the present invention will be 'apparentfrom the following description, reference being had to 'the accompanyingdrawings wherein a pre- 'fer'red embodiment of the present invention is'clearly shown.

In the -drawings:

'Figure 1 i's a side elevation of fa part of a carburetor showing theoutlet thereof |and [the throttle operating mechanism.

'Figure 2 is a fragmentary elevation 'of a part of the mechanism of Pig.1 showing 4the parts in operative position.

'Figure 3 -is a -fragmentary elevation of a 'modified form of throttle4Operating mechanism.

Figure 4 is a bottom plan view of Fig. 3 seen in the direction of the'arrow 4.

Figure 5 is an end elevation of a carburetor with 'the modified form oflthe invention -incorpora'ted therein.

-Fgure 6 is a fragmen'tary side elevation of a carburetor with themodified form of 'the invention showing the latterin section on the line6-6 of Fig. 5.

As shown in Fig. 1 a part of the carburetor housing is indicated at 2and it will be understood that the structural details of the carburetorare ent'irely immaterial so far as this invention is concerned. Thecarburetor is provided with an air inlet 4 and a mixture outlet passage6 through which combustible mixture is supplied to the engine, fuelbeing supplied in the carburetor in the usual way and being mixed withair therein. A flange 8 is provided for securing the carburetor in theconventional manner.

A choke valve 10, shown in dotted lines, is provided;

a in the air intake 4 to control the admission of air. This valve issecured to a shaft 12, which is off-center with respect to the Valve, sothat the valve is unbalanced and the direct effect of suction on thevalve itself tends to open the valve, if the pressure diiferentialacross the valve is increased. This valve is held closed at lowtemperatures to facilitate starting of the engine by the automatic chokemechanism, which is not shown herein because its construction is in noway material so far as the present invention is concerned. Thisautomatic choke mechanism may be of any conventional construction, asfor example, of the construction shown in the patent of Elmer Olson, No.2,615,694, of October 28, 1952.

In mechanisms of this kind, a thermostat is provided to hold the valvein closed position at low temperatures and a member subject to manifoldsuction is also connected to the valve and tends to pull the valve openagainst the force of the thermostat when the engine starts to run underits own power. Therefore, when the engine starts to run, the choke valveassumes a position where the forces of the thermostat and suction arebalanced. This mechanism is standard conventional construction and usedin most carburetors now on the market. i

The quantity of mixture supplied to the engine is controlled by athrottle valve 14, shown in dott'ed lines, which is secured to a shaft16, suitably journalled in the housing. The throttle is manuallyoperated through the medium of arm 18 loosely mounted on the throttleshaft and having an orifice 20 in which some form of Operatingconnection extending to the usual accelerator pedal is adapted to beconnected. The throttle is normally held in closed position by the usualthrottle return spring (not shown) and is manually moved to whateveropen position is desired to control the engine speed.

Connected to the throttle Operating arm 18 by the link 22 is a lever arm24' which operates a fuel pump. Neither this Operating connection northe pump constitutes any part of this invention.

The normal closed, or hot idle, position of the throttle is adjustablydetermined by the position of an adjustable stop screw 26 which isthreaded in a laterally projecting lug 28 integral with the arm 13. Aspring 30 holds the screw in any adjusted position and the end of suchscrew is adapted to engage a fixed stop lug 32 formed on the carburetorhousing.

As already stated herein, when the temperature is low it is desirable toincrease the idling speed of the engine to prevent possible stalling andunder such conditions the throttle is prevented from moving to its fullyclosed position by mechanism which will now be described, and this meansfor controlling the idling speed is positioned by the choke valve. Tothis end the choke valve has secured thereto a collar 34 having a lug 36integral there- With. Such lug engages a cooperating lug 38 integralwith a weighted member 40 rotatably mounted on the shaft 12 and providedwith a slot 42 which receives the bent over end 44 of an Operating link46. A similar bent over end of the link 46 is connected in an opening inan arm 48, pivotally mounted on a pin 50 screwed into the carburetorhousing. This arm is of the shape shown in Fig. 1 and at the right sideof such arm a fast idle cam 52 is formed. This cam is engaged by anadjustable stop screw 54, threaded in a laterally projecting lug 56integral with arm 18, said screw being held in any position ofadjustment by the spring 53. The cam 52 is so forrned that when thechoke valve is closed, the highest point of the cam is engaged by screw54 and the throttle is held at a cousiderably wider open position thanthe normal closed or hot idle position, the latter being indicated at Ain Fig. 1 and the fast idle position at B. As the choke moves towardopen position upon increase of engine temperature, the arm 48 is rotatedcounterclockwise so that the lowest point on the cam 52 `is ultimatelybrought into engagement with screw 54 and with the cam in such positionthe throttle will move to its normal idle position, if it is notmanually held open.

As stated, the position of the fast idle cam controls the position ofthe lever 18 and also the closed position of the throttle. The mechanismthrough the medium of which the loosely mounted lever 18 determines theposit'ion of the throttle will be described later.

It will be noted that the cam 52 comprises a series of steps 60 atdifferent distances from its axis of rotation. If the engine stops whenit is hot, with the choke valve wide open, upon closing of the throttlethe screw 54 will engage the lowermost step 60 and obviously the chokevalve cannot return to its closed position until the throttle is openedenough to disengage the screw E34 from the cam 52. Since it isnecessary, at any relatively low temperature, for the choke valve to bein closed position in order to start the engine and since it isdesirable to have the throttle open to a greater extent than the normalidle position for starting, means are provided to open the throttle farenough to be at the proper starting position and to disengage screw 54from the cam 52.

For this purpose a solenoid 62 is provided which is secured in anydesirable way to the carburetor housing in such a position that thearmature 64 of such solenoid is immediately above a laterally projectinglip integral with a lever 68 secured to the throttle shaft 16 and havingan opening 70 in which one end of spring 72 is received, the other endof such spring engaging a notch 74 in an arm '76 integral with andproiecting from the throttle Operating arm 18.

Normally when the solenoid is not energized the solenoid and throttleoccupy the position shown in Fig. 1 but the choke valve is in closedposition and the cam 52 is in fast idle position. At any time the engineis stopped after operation at normal temperature, the throttle andsolenoid would be as in Fig. 1, but the choke would be open and cam 52in the normal or hot idle position. If the solenoid is energized lever68 is moved to the Fig. 2 position, opening the throttle to the desiredextent and through spring 72 moving arm 18 clockwise to release the fastidle cam from screw 54 so that the choke can close and move the cam toits fast idle position.

When the cam 52 is in the fast idle position the throttle cannot movetoward closed position after the solenoid is deenergized because aprojecting toe 78 integral with lever 68 is engaged by an ofset portion80 of lever 18. Lever 18 being held in position by the fast idle cam,movement of the throttle toward closed position is stopped by said lever18.

When the throttle is operated manually the lever is moved in a clockwisedirection by the manual Operating connection and moves lever 68 and thethrottle in a clockwise direction through engagement of the offset 80with the toe 78, to open the throttle. On closing of the throttle themovement of lever 18 pulls the throttle to- Ward closed position throughthe medium of spring 72.

The structure of the solenoid is Wholly immaterial so far as the presentinvention is concerned and also the details of its control circuit. Anysuitable circuit can be provided, by means of which the energization ofthe solenoid is effected when the starter control circuit is closed andis continued as long as said circuit is closed. When the solenoid isdeenergized the throttle will take Whatever position is determined bythe position of the fast idle cam. If the temperature is below somepredetermined degree the throttle will be in the position of Fig. 2 andif the temperature is above such predetermined degree, but less thannormal Operating temperature, the throttle will be Somewhere between theFig. 2 and Fig. l positions, depending upon the position of the cam 52.

Coming now to the second form of the invention, which is shown in Figs.3 to 6 inclusive, the arrangement of parts is slightly different and thefunction also is slightly different, the throttle being moved topartially open position as soon as the engine stops instead of at thetime the starter circuit is closed, and closing movements of thethrottle which might cause engine stalling being prevented.

nthis form of the invention the throttle shaft is designated 90 and themanually operable throttle actuating lever comparable to lever 18 at 92.This lever is also loose on the throttle shaft as is the lever 18 andalso operates a fuel pump through connections such as shown in Fig. 1.Secured tothe throttle shaft is a lever 94 and this lever has aprojecting toe 96 integral therewith which is engaged by a laterallyoffset portion 98 of the lever 92 as the latter is moved clockwise toeffect opening of the throttle. The lever 94 is connected to lever 92 bya spring 100 similar to the spring 72 and when lever 92 is returned tonormal position upon release of the accelerator pedal the spring pullsthe `lever 94 in a counterclockwise direction to move the throttletoward closed position. Stop screws 102 and 104 which correspond toscrews 26 and 54, respectively, are carried by lever 94 which is securedto the throttle shaft instead of by a lever loose on the shaft as in thedevice shown in Fig. 1. However, these screws cooperate with a fixedstop 106 for normal idling and a movable fast idle cam 108, similar tocam 52 on an arm 110 which is connected to the choke valve by a rodsimilar to rod 46 to be moved thereby in the same way as arm 48 and cam52, so as to control the idle position of the throttle in the same wayas previously described.

To position the throttle in the proper place for starting, to releasethe fast idle cam from the screw 104 and to retard the closing of thethrottle upon release of the accelerator pedal, a device movable inresponse to manifold suction is employed. This device comprises adiaphragm housing 114 which is secured to the carburetor housing in anysuitable way, as by means of a bracket 116, shown in Fig. 5, which isattached by screws to the carburetor body and to which the diaphragmchamber is secured by screws.

The chamber 114 is formed of two parts 118 and 120 which are joinedtogether in any suitable Way to form a fiuid-tight joint and a flexiblediaphragm 122 of any suitable material is clamped between the two parts118 and 120. Extending from the member 120 is a coupling member 124having a passage 126 therethrough. This pas- Sage may be threaded toreceive the reduced neck 128 of a nipple 130 as shown in Fig. 6, and thenipple may be connected in any suitable way to a conduit leading to theintake passage at some point posterior to the throttle. A spring 131 isreceived in the passage 126 and normally forces the diaphragm to theright to the position shown in Fig. 6.

A rod 132 is slidably received in a bushing 134 mounted in thesupporting plate 116 and a reduced extension of this rod extends throughthe diaphragm and reinforcing plates 136 and 138 and is riveted to holdthe assembly togcther. An elongated nut 140 with a closed end is screwedso that by movement of the nut the effective length of the rod can bemodified. This nut is adapted to engage a pin 142 extending from theleverarm 94 and when the spring is expanded the lever 94 is moved to theright to open the throttle to an extent determined by the adjustment ofthe nut 140.

The function of the mechanism described is obvious. Whenever the engineis inoperative and no suction is effective on the diaphragm 122 thelatter and rod 132 are moved to the right to move the throttle to thedesired open position for starting. When moved to this position thescrew 104 no longer engages the fast idle cam 108 so that there is nointerference With the movement of the choke valve to closed position orto any other position, as determined by the temperature.

If, when the engine is Operating, the throttle is released by theoperator and the engine continues'to run normally, the suction effectiveon the diaphragm Will overcome the pressure of the spring 131 and willhold the rod 132 in a position far enough to the left toprevent anyeffect of the rod on the position of the throttle, it being understoodthat during normal operation of the engine the mechanism is withouteffect in controlling the throttle movements. If, however, upon releaseof the accelerator pedal and a rapid closing movement of the throttlethe engine speed decreases so rapidly that there is a tendency for theengine to stall, the engine speed becomes so low that the suction willnot overcome the pressure of spring 131, rod 132 will move to the rightpreventing closing of the throttle sufi'iciently for stalling to takeplace. This form of the device is particularly useful in Vehiclesequipped with certain automatic transmissions in which there is nodriving connection between the vehicle and the engine When the vehicleslows down.

There may be a ball check valve provided in the suction passage betweenthe intake passage and the diaphragm Chamber which is so arranged thatmovement of the diaphragm toward the right is free, but movement towardthe left is retarded. The purpose of this device is o-bvious from thefollowing. Whenever the rod 132 is moved to the right, as previouslydescn'bed when the engine tends to stall, the throttle is opened enoughto keep the engine going and the engine speed picks up. It is desiredthat the throttle return toward normal idle; position to preventoperation of the engine at higher speed than necessary, but it is notdesired to permit this movement too rapidly or there would be a furthertendency to stall. As the engine speeds up the suction becomes effectiveto move the diaphragm toward the left and the check valve is provided toprevent too rapid movement in response to this increase in suction.

As shown in Fig. 6 a small passage 144 is provided in the neck 128 of'the nipple and this communicates with an enlarged Chamber 146 in whicha ball valve 148 is retained between the end of passage 144 and a pin150, but any suitable ball retaining means may be used.. In addition tothe passage 144 there is a restricted passage 152. through which suctionis communicated to the diaphragm. Upon a reduction of suction the balldoes not block the passage 144 so the effect is immediate and movementof the diaphragm and rod 132 to the right is not retarded, but uponincrease of suction in conduit 130 the ball is moved to block passage144 so that the suction effective on the diaphragm is communicatedthereto only through the small passage 152 and movementV of thediaphragm and rod 132 is obviously retarded. In this way closing of thethrottle after engagement of pin 142 by rod 132 is delayed.

While the embodiment of the present invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

1. In a carburetor having an air inlet, a mixtureoutlet passage, a chokevalve controlling the admission of air' and a throttle valve forregulating the quantity of combustible mixturc supplied to the engine;means for controlling the operation of said throttle Valve including amember operable by said choke valve when moved to closed position forholding said throttle valve open to a greater degree than its normalidle position, in order to secure faster than normal idling, said memberbeing movable by -the choke valve during its opening movement to aposition where movement of the throttle to normal idle position ispermitted and being effective When in such position to prevent return ofthe choke valve to its closed position, means for holding said member insuch position when the throttle is in normal idle position, and meansoperated automatically when the engine is inoperative for opening thethrottle at least as far as the fast idle position to release saidmember and perinit its return to normal position.

2. In a carburetor having an air inlet, a mixture outlet passage, achoke valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for controlling the operation of said throttle valve including afmember operable by said choke valve when moved to ananasa closedposition for holding said throttle valve open to a greater degree thanits normal idle position, in order to secure faster than normal idling,said. member being movable by the choke valve during its openingmovement to a position Where movement of the throttle to normal idleposition is permitted and being effective when in such position toprevent return of the choke valve to its closed position, means forholding said member in such position when the throttle is in the normalidle position, and a solenoid adapted to be energized when the enginestarting means is rendered operative, said solenoid being operative Whenenergized to open Vthe throttle at least as far as its fast idleposition to release said member and permit its return to normalposition.

3. In a carburetor having an air inlet, a mixture outlet passage, achoke valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for controlling the operation of said throttle valve including amember operable by said choke valve When moved to closed position forholding said throttle valve open to a greater degree than its normalidle position, in order to secure faster than normal idling, said memberbeing movable by the choke valve during its opening movement to aposition Where movement of the throttle to normal idle position ispermitted and being effective when in such position to prevent return ofthe chol-:e valve to its closed position, means for holding said memberin such position when the throttle is in normal idle position, andsuction Controlled means operable automatically When the engine ceasesto operate under its own power to open the throttle at least as far asits fast idle position to release said member and permit its return tonormal position.

4. In a carburetor having an air inlet, a mixture outlet passage, acholce valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for controlling the operation of said throttle valve including amember operable by said choke valve when moved to closed position forholding said throttle valve open to a greater degree than normal idling,said member being movable by the choke valve during its opening movementto a position Where movement of the throttle to normal idle position ispermitted and being effective When in such position to prevent return ofthe choke valve to its closed position, means for holding said member insuch position when the throttle is in normal idle position, and suctionControlled means movable upon a reduction in the suction effectivethereon, to a position where said means is effective to prevent closingmovement of the throttle to its normal idle position v/here'oy releaseof said member and return thereof to its normal position is eifected.

5. In a carburetor having an air inlet, a mixture outlet passage, achoke valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for controlling the operation of said throttle valve including amember movable by the choke valve to a position to hold the throttleopen beyond normal idle position when the choke valve is closed, a stopmember operatively connected to said throttle and engaging said firstmember, said stop member being effective to hold said first-named memberin the position to which it has been moved by the choke valve andprcvent closing of the latter when the throttle is closed and meansoperable automatically when the engine is inoperative to hold thethrottle open sufiiciently to disengage the stop member from said firstmember, to permit movement of said first member to its initial positionand closing of the choke valve.

6. ln a carburetor' having an air inlet, a mixture outlet passage, achoke valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for conu trolling the operation of said throttle valve including amember movable by the choke valve to a position to hold the throttleopen beyond normal idle position when the eboi-:e valve is closed, astop member operatively coni cted to said throttle and engaging saidfirst member, stop member being effective to hold said first-namedmember in the position to which it has been moved by the choke valve andprevent closing of the latter When the throttle is closed, a solenoidadapted to be cnergized When the engine starting means is renderedoperative, an arm operatively connected to the throttle and actuated bysaid solenoid When energized to move the throttle toward open positionsuft'icicntly to disengage said stop member from the member movable bythe choke valve to permit movement of said first member to its initialposition and closing of the choke valve.

7. in a carburetor having an air inlet, a mixture outlet passage, achoke valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for controlling the operation of said throttle valve including amember movable by the choke valve to a position to hold the throttleopen beyond normal idle position when the choke valve is closed, a shaftsupporting the throttle rotatably mounted in the mixture outlet passage,an Operating arm rotatable on the throttle shaft but operativelyconnected thereto, a stop member carried by said Operating arm andengageable with said first-named member, said stop member beingeffective to hold said first-named member in the position to which ithas been moved by the choke valve and prevent closing of the latter Whenthe throttle is closed, a solenoid adapted to be energized When theengine starting means is rendered operative, an arm secured to thethrottle shaft and movable by the solenoid When energized to move thethrottle to a position Where the aforesaid stop member is not inposition to engage the member movable by the choke valve to permitmovement of said first member to its initial position and closing of thechoke valve.

8. ln a carburetor' having an air inlet, a mixture Outlet passage, achoke valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for controlling the operation of said throttle valve including amember movable by the choke valve to determine the idling position ofthe throttle, said member being so positioned When the choke valve isopened that the throttle can be closed to its normal idle position andmovable to a position to hold the throttle open to a greater extent Whenthe choke is closed, a stop member operatively connected to the throttlevalve movable therewith and engageable with said first-named member tolimit the closing movement of the throttle, said stop member beingeffective to hold said first-named member in the position to which ithas been moved by the choke valve and prevent closing of the latter whenthe throttle is closed, an Operating arm secured to the throttle, andautomatic actuating means for said arm effective When the engine isinoperative to move said arm and open the throttle suiciently to movesaid stop member and disengage it from said first-named member to permitmovement of said first member' to its initial position and closing ofthe choke valve.

9. In a carburetor having an air inlet, a mixture outlet passage, achoke valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for controlling the operation of said throttle valve including amember movable by the choke valve to determine the idling position ofthe'throttle, said member being so positioned when the choke valve isopened that the throttle can be 'closed to its normal idle position andmovable to a position to hold the throttle open to a greater extent whenthe choke is closed, a stop member operatively connected to thevthrottle valve and engageable with said lfirsthamed member to limit theclosing movement of the throttle, said stop member being effective tohold said first-named member in the position to which it has been movedby the choke valve and prevent closing of the latter when the throttleis closed, an operating arm secured to the throttle, and automatic meansoperative concurrently With the starting of the engine to move said armand open the throttle sufficiently to disengage said stop member fromthe first-named member to permit movement of said first member to itsinitial position and closing of the choke valve. w

10. In alcarburetor having an air inlet, a mixture outlet passage, achoke valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for controlling the operation of said throttle valve including amember movable by the choke valve to determine the idling position ofthe throttle, said member being so positioned when the choke valve isopened that the throttle can be closed to its normal idle position andmovable to a position to hold the throttle open to a greater extent whenthe choke is closed, a stop member operatively connected to the throttlevalve and engageable with said firstnamed member to limit the closingmovement of the throttle, said stop member being effective to hold saidfirst-named member in the position to which it has been moved by thechoke valve and prevent closing of the latter when the throttle isclosed, an Operating arm secured to the throttle, and a solenoid adaptedto be energized concurrently with the starting of the engine andeffective when energized to engage said arm and move the throttle towardopen position far enough to disengage said stop member from thefirst-named member to permit movement of said first member to itsinitial position and closing of the choke valve.

11. In a carburetor having an air inlet, a mixture outlet passage, achoke valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for controlling the operation of said throttle valve including amember movable to different positions to variably control the idlingposition of the throttle, a stop member operatively connected to thethrottle and engageable with said first-named member to limit theclosing movement of the throttle, said stop member being effective tohold said first-named member in the position to which it has been movedby the choke valve and prevent closing of the latter when the throttleis closed, an Operating arm for the throttle, and automatic meansoperatble concurrently with the starting of the engine and efiective tooperate said arm and move the throttle toward open position suflicientlyto disengage the stop member from the first-named member to permitmovement of said first member to its initial position and closing of thechoke valve thus locating the throttle in the best position forstarting.

12. In a carburetor having an air inlet, a mixture outlet passage, achoke valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for controlling the operation of said throttle valve including amember movable to different positions to variably control the idlingposition of the throttle, a stop member operatively connected to thethrottle and engageable With said first-named member to limit theclosing movement of the throttle, said stop member being effective tohold said first-named member in the position to which it has been movedby the choke valve and prevent closing of the latter when the throttleis closed, an Operating arm for the throttle, means operable when theengine is inoperative to engage said arm and hold the throttle open toan extent sullcient to move said stop member to a position where it isdisengaged from and permits movement of said first member to its initialposition and closing of the choke valve thus locating the throttle inthe best position for starting, and means operable by engine suctionwhen the engine is Operating under its own power for rendering saidlast-named means ineffective.

13. In a carburetor having an air inlet, a mixture outlet passage, achoke valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for controlling the operation of said throttle valve including amember movable by the choke valve to determine the idling position ofthe throttle, said member being so positioned when the choke valve isopened that the throttle can be closed to its normal idle position andmovable to a position to hold the throttle open to a greater extent whenthe choke is closed, a stop member operatively connected to the throttlevalve and engageable with said first-named member to limit the closingmovement of the throttle, said stop member being effective to hold saidfirst-named member in the position to which it has been moved by thechoke valve and prevent closing of the latter when the throttle isclosed, an operating arm secured to the throttle, means operable whenthe engine is inoperative to engage said arm and hold the throttlesufliciently open and to move said stop member to a position where itcannot engage With and thus permits movement of said first member to itsinitial position and closing of the choke valve, and means operated byengine suction When the engine is Operating under its own power torender said last-named means ineffective.

14, In a carburetor having an air inlet, a mixture outlet passage, achoke valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for controlling the operation of said throttle valve including athrottle shaft rotatably mounted in the mixture outlet passage, anOperating arm rotatable on the throttle shaft but operatively connectedthereto, a member movable to different positions to variably control theidling position of the throttle, an arm secured to the throttle shaft, astop member carried by said last-named arm and engageable with thefirst-named member to limit the closing movement of the throttle, saidstop member being effective to hold said first-namedcmember in theposition to which it has been moved by the choke valve and preventclosing of the latter when the throttle is closed, automatic meansoperable when the engine is inoperative to engage said last-named aimand move the throttle sufficiently toward open position to move the stopmember to a position where engagement of said member with saidfirstnamed member is prevented permitting movement of said first memberto its initial position and closing of choke valve and means operated byengine suction when the engine is self-operative to render saidautomatic means inoperative.

15. In a carburetor having an air inlet, a mixture outlet passage, achoke valve controlling the admission of air and a throttle valve forregulating the quantity of combustible mixture supplied to the engine;means for controlling the operation of said throttle valve including amember connected to the choke valve for movement therewith and movableto different positions as the choke valve is moved to variably controlthe idling position of the throttle, a stop member operatively connectedwith the throttle and engageable with said first-named member to limitthe closing movement of the throttle valve, said stop member beingeffective when in engagement with said first-named member to preventmovement of such member in a direction to permit closing of the chokevalve When the throttle is closed, automatic means operable when theengine is inoperative to disengage said stop member from the first-namedmember in order to permit closing of the choke valve to facilitatestarting of the engine, and means operated by engine suction when theengine starts to operate under its own power to render said automaticmeans inoperative.

16. In a carburetor having a mixture outlet passage,

1 1 a throttle valve for regulating the passage of combustible mixturethrough said outlet, an air inlet and a choke valve adapted to beautomatically moved to different positions to control the admission ofair through said inlet, means for controlling the throttle valvecomprising a member connected to the choke valve for movement therewithand movable to different positions as the choke valve is moved tovariably control the idling position of the throttle, a stop memberoperatively connected with the throttle valve, said stop member beingeffective when in engagement With said first-named member to preventmovement of such member in a direction to permit closing of the chokevalve in open position if the engine is stopped when relatively hot, andautomatic means operable'concurrently With the starting of the engine todisengage said stop member from the first-named member and per-mitmovement of the choke valve to closed position before the engine isstarted.

References Cited in the file of this patent UNITED STATES PATENTS2,102,909 Paton Dec. 21, 1937 2,190,738 Schweiss Feb. 20, 1940 2,307,486Carlson Ian. 5, 1943 2,325,372 Coffey July 27, 1943 2,36l,103 IssigonisOct. 24, 1944 2,575,384 Horton Nov. 20, 1951 2,597,606 Winkler May 20,1952

